Amphiregulin stimulates human chorionic gonadotropin expression by inducing ERK1/2-mediated ID3 expression in trophoblast cells

Gene expression profile of human placental villous pericytes in the first trimester - An analysis by single-cell RNA sequencing

Mesenchymal cells within theplacental villi play a crucial role in shaping the morphology of branching structures and driving the development of blood vessels. However, the markers and functions of placental villous pericytes (PVPs) as distinct subgroups of placental villous mesenchymal cells, remain unclear. Therefore, in this study, the markers and functions of PVPs were investigated. Single-cell sequencing data from the first-trimester placental villi was obtained and the Seurat tool was used to identify PVP markers. Gene Ontology (GO) analysis of specific genes was performed using the DAVID database. The Cellchat tool was employed to investigate the interaction signals between the PVPs and other cells. Expression of the PVP markers was confirmed using immunofluorescence. Presence of extracellular vesicles in the placental villous mesenchyme and PVPs was examined by transmission electron microscopy. Our findings revealed that renin (REN) and amphiregulin (AREG)-positive fibroblasts in the placental villi specifically expressed several classic pericyte markers. In the first trimester, certain conserved functions of pericytes were observed and they displayed tissue-specific functions such as in the integrin-mediated signaling pathway and extracellular exosomes. Moreover, the placental villous mesenchyme was found to be rich in extracellular vesicles. AREG is specifically transcribed in the first trimester PVPs, however, its protein was located in syncytiotrophoblasts. These insights contribute to a comprehensive understanding of early placental development and offer new therapeutic targets for placenta-derived pregnancy complications.

Investigation of Serum Amphiregulin Concentrations in Pregnant Women Diagnosed with Isolated Fetal Growth Restriction in the Third Trimester

OBJECTIVE

We aimed to investigate serum amphiregulin (AREG) concentrations in pregnant women with isolated fetal growth restriction (FGR) in the third trimester.

MATERIALS AND METHODS

This cross-sectional study was conducted with 90 pregnant women who applied to the Umraniye Training and Research Hospital Gynecology and Obstetrics Clinic between January 2022 and May 2022. The FGR group consisted of 45 pregnant women diagnosed with FGR in the third trimester, and the control group consisted of 45 healthy pregnant women matched with the FGR group in terms of age and body mass index (BMI). Demographic characteristics, ultrasound findings, and neonatal outcomes were noted. As a primary outcome, the two groups were compared for maternal serum AREG concentrations.

RESULTS

Both groups were similar in terms of demographic characteristics (p>0.05). While fetal BPD, AC, and FL measurements in the group diagnosed with FGR were significantly lower than in the control group, umbilical artery Doppler PI and S/D were higher (p=0.000, for all). Gestational age at birth, newborn birth weight, birth height, and 1-minute Apgar score were significantly lower and the NICU admission rate was higher in the FGR group (p=0.000, p=0.000, p=0.000, p=0.027, p=0.011 respectively). Gestational age at blood sampling for AREG was similar in both groups (p=0.869). While maternal serum AREG concentration was 969.39 ng/L in the FGR group, it was 795.20 ng/L in the control group (p=0.018). AUC analysis of AREG for estimation of FGR in ROC analysis was 0.57 (p<0.247, 95% CI=0.44-0.69). The optimal threshold value for FGR estimation of maternal serum AREG concentration was determined as 874.03 ng/L with 55% sensitivity and 55% specificity.

CONCLUSION

High maternal serum AREG concentrations appear to be associated with isolated FGR in the third trimester. The pathways through which AREG modulates fetal growth remain to be investigated.

Human chorionic gonadotrophin indirectly activates peripheral γδT cells to produce interleukin-10 during early pregnancy

BACKGROUNDS

The immunomodulatory properties of human chorionic gonadotrophin (hCG) have been identified to be critical for successful pregnancy. However, the effects of hCG on peripheral γδT cells during early pregnancy have not been reported previously.

METHODS

We cocultured the purified γδT cells and peripheral blood mononuclear cells (PBMCs) with early pregnancy-relevant hCG concentrations and investigated the changes in the immune functional characteristics of γδT cells via flow cytometry assays.

RESULTS

The ratios of CD69+ and IL-10+ γδT cells were increased in early pregnant women compared to nonpregnant women. γδT cells expressed low levels of the mannose receptor (CD206) instead of the classical hCG/LH receptor for hCG. The direct treatment of purified γδT cells with early pregnancy-relevant hCG concentrations may have no significant effects on their immune functions. Interestingly, when PBMCs were treated with the same broad range of hCG concentrations, the ratios of CD69+ and IL-10+ γδT cells to total γδT cells were significantly increased.

CONCLUSION

Certain early pregnancy-relevant hCG concentrations could enhance the ratios of peripheral CD69+ and IL-10+ γδT cells, contributing to the activation of γδT cells and immunological tolerance during early pregnancy. However, these affects may not be strongly mediated by direct ligand-receptor interactions and they may highly depend on immune microenvironment. Our novel observations propose a perspective into the endocrine-immune dialog that exists between the fetus and maternal immune cells.

Activation of G protein-coupled estrogen receptor stimulates placental human chorionic gonadotropin expression through PKA-CREB signaling

The placenta-secreted human chorionic gonadotropin (hCG) is a hormone that plays a critical role in inducing ovarian progesterone production, which is required for maintaining normal pregnancy. The bioavailability of hCG depends on the expression of the beta-subunit of hCG (hCG-β) which is encoded by the chorionic gonadotropin beta (CGB) gene. G protein-coupled estrogen receptor (GPER) is a membrane estrogen receptor involved in non-genomic estrogen signaling. Estradiol (E2) has been shown to stimulate hCG production. However, the role of the GPER in regulating CGB expression remains unknown. In the present study, our results revealed that treatment with G1 upregulated CGB expression in two human choriocarcinoma cell lines, BeWo and JEG-3, and primary human cytotrophoblast cells. In addition, G1 treatment activated the cAMP-response element binding protein (CREB). Using a pharmacological inhibitor and siRNA-mediated knockdown approach, we showed that the stimulatory effect of G1 on CGB expression is mediated by the protein kinase A (PKA)-CREB signaling pathway. This study increases the understanding of the role of GPER in the human placenta. In addition, our results provide important insights into the molecular mechanisms that mediate hCG expression, which may lead to the development of alternative therapeutic approaches for treating placental diseases.

WNK1 mediates amphiregulin-induced MMP9 expression and cell invasion in human extravillous trophoblast cells

The invasion of human extravillous trophoblast (EVT) cells is a critical event required for a successful pregnancy. Amphiregulin, a ligand of the epidermal growth factor receptor (EGFR), has been shown to stimulate cell invasion in an immortalized human EVT cell line, HTR-8/SVneo. The with-no-lysine kinase 1 (WNK1) is involved in regulating cell invasion. It is known that WNK1 is expressed in the human placenta, but its role in human EVT cells remains unknown. In the present study, we show that AREG treatment phosphorylated WNK1 at Thr60 in both HTR-8/SVneo and primary human EVT cells. The stimulatory effect of AREG on WNK1 phosphorylation was mediated by the activation of PI3K/AKT, but not the ERK1/2 signaling pathway. AREG upregulated matrix metalloproteinase 9 (MMP9) but not MMP2. In addition, cell invasiveness was increased in response to the treatment of AREG. Using the siRNA-mediated knockdown approach, our results showed that the knockdown of WNK1 attenuated the AREG-induced upregulation of MMP9 expression and cell invasion. Moreover, the expression of WNK1 was downregulated in the placentas with preeclampsia, a disease resulting from insufficiency of EVT cell invasion during pregnancy. This study discovers the physiological function of WNK1 in human EVT cells and provides important insights into the regulation of MMP9 and cell invasion in human EVT cells.

GDF-11 downregulates placental human chorionic gonadotropin expression by activating SMAD2/3 signaling

BACKGROUND

The production of human chorionic gonadotropin (hCG) by the placental trophoblast cells is essential for maintaining a normal pregnancy. Aberrant hCG levels are associated with reproductive disorders. The protein of hCG is a dimer consisting of an α subunit and a β subunit. The β subunit is encoded by the CGB gene and is unique to hCG. Growth differentiation factor-11 (GDF-11), a member of the transforming growth factor-β (TGF-β) superfamily, is expressed in the human placenta and can stimulate trophoblast cell invasion. However, whether the expression of CGB and the production of hCG are regulated by GDF-11 remains undetermined.

METHODS

Two human choriocarcinoma cell lines, BeWo and JEG-3, and primary cultures of human cytotrophoblast (CTB) cells were used as experimental models. The effects of GDF-11 on CGB expression and hCG production, as well as the underlying mechanisms, were explored by a series of in vitro experiments.

RESULTS

Our results show that treatment of GDF-11 downregulates the expression of CGB and the production of hCG in both BeWo and JEG-3 cells as well as in primary CTB cells. Using a pharmacological inhibitor and siRNA-mediated approach, we reveal that both ALK4 and ALK5 are required for the GDF-11-induced downregulation of CGB expression. In addition, treatment of GDF-11 activates SMAD2/3 but not SMAD1/5/8 signaling pathways. Moreover, both SMAD2 and SMAD3 are involved in the GDF-11-downregulated CGB expression. ELISA results show that the GDF-11-suppressed hCG production requires the ALK4/5-mediated activation of SMAD2/3 signaling pathways.

CONCLUSIONS

This study not only discovers the biological function of GDF-11 in the human placenta but also provides important insights into the regulation of the expression of hCG. Video Abstract.